Solar simulator is an important applic ation in non-imaging optical system.The uniformity is an important index of the solar simulator,and the optical integrator is a key e lement to achieve the uniformity of solar simulator.The optical integrator is composed of element lenses.Th e number and shape of the element lenses directly affect the uniformity of the solar simulator.In o rder to study the effect, LIGHTTOOLS simulation analysis method is used.The effect of 6different numbers of element lenses on the uniformity is studied,and also the effect of 2differen t shapes of element lens to the uniformity is studied.Analysis results show some important conclusions,such as t he more element lenses are used in optical integrator,the uniformity can be high er,and the optical length can be shorter,also the radiation surface can get more energy.Also the influence of the element lenses′ numbers on the uniformity is gradually weakened,and the regular hexagon structure is better than t he square structure,when a circle irradiation surface is required.The conclusions derived from this p aper provide an important reference for the design and selection of the optical integrator in solar simulator.